Final answer:
Begin cutting a triangular one length haircut by creating a central guideline at the nape of the neck and cutting straight across with the hair at zero elevation. Move outward from the center, keeping the length consistent. Angle your fingers slightly at the front to maintain the triangular shape.
Step-by-step explanation:
To begin cutting hair on a triangular one length below the shoulders haircut, you need to establish a guideline. The guideline is typically a straight line that sets the length for the rest of the haircut. Start by sectioning the hair. Divide the hair at the nape of the neck into a central section. This section will be your initial guide. Wet the hair, as this simplifies the cutting process and helps achieve a more precise cut.
Comb the hair down and hold it between your fingers at the desired length, typically just below the shoulder. Make your first cut straight across, ensuring that this first section is cut at a zero elevation to maintain a strong perimeter for the one-length look. It's essential to check that the hair is evenly distributed and to cut straight to maintain the triangular shape without layers.
After establishing the first central guide, continue to move out to the sides, always bringing the hair back to the center guide to keep the length consistent. This technique prevents the haircut from becoming rounded, as bringing the hair straight down beside the head when cutting would create a slightly rounded shape due to the head's curvature.
Remember, precision is key. Always cross-check your work by taking horizontal sections and making sure that they are the same length from every angle. Once you reach the front, slightly angle your fingers to respect the natural fall of the hair but still maintain the overall triangular shape.